Area Forecast Discussion
Issued by NWS Medford, OR
FXUS66 KMFR 310403
Area Forecast Discussion
National Weather Service Medford OR
903 PM PDT SAT JUL 30 2016
Updated Discussion and Fire Weather
The going forecast is well on track, so no updates are needed
tonight. We did cancel the fire weather watch for FWZ 624 for
Sunday due to insufficient wind. A Red Flag Warning is in effect
and looks on track for FWZ285 for tomorrow and Watches do remain
in effect for Monday for both FWZ 285 and 624.
Just before 5 PM PDT a thunderstorm developed in far Eastern Lake
County. While a handful of in cloud lightning ripples were
detected, there were no cloud to ground strikes reported from
that cell by lightning detection. More recently, since 8 PM PDT,
a strong thunderstorms developed east of Fort Bidwell in far
eastern Modoc and Washoe County, dropping some cloud to ground
strikes. All in all, no cloud to ground strikes in our Medford
forecast area, but quite close.
Meanwhile, across the forecast area, high temperatures were
around 5 degrees cooler today than they were on Friday. The Bybee
Creek Fire has been reported to have grown to 325 acres as of late
this afternoon. Satellite imagery shows some smoke blowing across
the Cascade Crest from that fire under a west flow now. Suspect
some will drain into the upper Rogue River drainage overnight as
the inversion sets in and light northeast drainage winds develop.
.FIRE WEATHER...Updated 855 PM PDT Saturday, 30 July 2016...
Please see above section regarding the Bybee Creek Fire. We had
1-2 hours of critical fire weather conditions at 3 locations in
the Modoc today, just short of the 3 hour duration needed to
constitute Red Flag conditions. There is concern for gusty winds
and low relative humidities for the next few afternoons/early
evening hours starting Sunday. The Red Flag Warning for a good
portion of FWZ 285 remains in effect for Sunday afternoon and
early evening. The fire weather watch for Sunday for southeast FWZ
624 for Sunday afternoon and evening has been cancelled because
winds are not expected to be high enough for critical fire weather
conditions there based on the zone specific criteria.
The models show Monday and possibly Tuesday being windier. An
upper low is expected to drop southeast towards northwest
Washington Monday afternoon with an increasing southwest flow
ahead of the low. For now we have the Fire Weather Watches out
for FWZ 285 and southeast portions of FWZ 624 and it is possible
this watch may need to be expanded. BTL/Petrucelli
.AVIATION..31/00Z TAF cycle...VFR conditions will continue for the
next 24 hours for inland terminals. At the coast, VFR cigs will
continue into early this evening then areas of MVFR/IFR will develop
from Cape Blanco northward. Current TAF for KOTH shows MVFR cigs
returning around 4Z, then lowering to IFR around 7Z. However,
confidence is low to medium on the timing of when ceilings may
lower. Moderate to strong and gusty north winds are expected through
this evening for most areas along the coast and offshore. Scattered
cumulus buildups are expected over the higher terrain of northern
California into south central Oregon through early evening, but no
thunderstorms are expected. -CC
.MARINE...Updated 530 PM PDT Saturday 30 Jul 2016...A thermal trough
along the coast and high pressure offshore will continue to produce
moderate to strong north winds and steep to very steep wind driven
seas through late Sunday. Hazardous seas are expected over most the
waters through tonight with gales south of Cape Blanco. On Sunday
expect Gales and hazardous seas south of Cape Blanco and small
craft advisory conditions to the north. The most hazardous winds
and seas are expected beyond 5 nm from shore. Winds will decrease
slightly on Monday but still expect a mix of steep to very steep
seas over the waters as well as gusty winds south of Cape Blanco.
Isolated gales are also possible Monday afternoon and evening from
15 to 25 nm from shore south of Brookings. Winds are expected to
rise to gales again by Tuesday evening and may continue through late
next week. -CC
.PREV DISCUSSION... /Issued 243 PM PDT SAT JUL 30 2016/
SHORT TERM...Cumulus clouds are forming over the same area as
yesterday, mainly in southern Lake County and Modoc County. Expect
more development to the west into the Medicine Lake area but the
atmosphere capped along with little upper level dynamics.
Temperatures are running up to 5 degrees cooler than yesterday
with humidity down a few percentage point. Expect Sunday
morning`s low temperatures to be 5 to 10 degrees cooler than this
morning also. This slight cooling trend will continue into Sunday
as the ridge weakens and starts to shift east in response to a
trough passing to the north of our forecast area tonight. This
upper level trough will push a dry cold front inland an help to
increase winds across eastern Oregon and NE California and will
present fire weather concerns due to the atmosphere being very
dry. Areas west of the Cascades, including the Shasta Valley, will
also see an uptick in wind Sunday afternoon and evening but wind
will not be as strong as to the east.
Breezy West winds continue into Monday and could be stronger for
the east side. Increasing onshore flow Monday night will bring low
clouds into the Umpqua Basin and high temperatures on Tuesday
could be up to 5 degrees below seasonal norms, which for Medford
is in the lower 90s.
LONG TERM...(Wednesday to Saturday)...As usual with these
summertime fronts, the cold air is fairly shallow and daytime
temperatures are expected to warm back up Wednesday and Thursday
while nighttime temperatures will be closer to seasonal norm or
slightly below. Southwest Oregon and western Siskiyou County will
have to contend with the return of thermal trough and offshore
flow which will keep conditions warm and dry (in term of nighttime
humidity). Both the GFS and ECMWF are in fairly good agreement
that an upper level low pressure will drop into southern BC or
possible NW Washington with a broad trough down as far south as
northern California per EC and just to southern Oregon per GFS.
This will send another round of cold front into our forecast area.
After a few days of warming, temperatures could lower back toward
or even turn lower than seasonal norms in the second half of next
week. Gusty winds will be a concern again toward the end of next
OR...Fire Weather Watch from Monday afternoon through Monday evening
CA...Fire Weather Watch from Monday afternoon through Monday evening
Red Flag Warning from noon to 9 PM PDT Sunday for CAZ285.
Pacific Coastal Waters...
- Small Craft Advisory until 2 AM PDT Tuesday for PZZ350-356.
- Gale Warning until 5 AM PDT Sunday for PZZ356.
- Hazardous Seas Warning until 5 AM PDT Monday for PZZ356.
- Hazardous Seas Warning until 5 AM PDT Sunday for PZZ350-370.
- Small Craft Advisory from 5 AM Sunday to 2 AM PDT Tuesday for
- Gale Warning until 5 AM PDT Monday for PZZ376.
- Hazardous Seas Warning until 2 AM PDT Tuesday for PZZ376.